• Syrjälä, Seppo
• Keränen, Kimmo
• Silvennoinen, Mikko
• Hakkarainen, Jehki
• Salmi, Timo
• Schorpp, Marcus
• Ojapalo, Anneli
• Mäkinen, Jukka-Tapani
• Karioja, Pentti
• Hoskio, Pekka

Abstract

A microscope add-on device to a 1.3 Mpix camera phone was selected as ademonstrator system for testing inmould integration of electronic substratesand plastic optics. Optical design of the device was quite challenging due tothe fact that illumination system needed to be integrated with a doubleaspheric singlet lens structure as a single optical piece. The designedimaging lens resolution was adequate to resolve 10 ìm features with a mobilephone camera. In the illumination optics the light from LEDs embedded into theplastic structure was collected and guided to the surface that was imaged.Illumination was designed to be uniform and adequately bright to achieve highresolution images with the camera phone. Lens mould design was tested by usinginjection moulding simulation software. The critical mould optical surfaceswere designed as separate insert parts. Final shapes producing lens surfaceswere tooled by diamond turning on nickel coatings. Electronic circuit boardinserts with bonded bare LED chips and packaged SMD LEDs were assembled to themould and then overmoulded with optical grade PMMA. Experiences proved thatinmould integration of electronic substrates, bare LED chips and highresolution imaging optics in injection-compression moulding process isfeasible. The yield of embedded packaged and also bare chip components wasclose to 100% after the right injection moulding process parameters werefound. Prototype add-on system was characterized by testing the imagingproperties of the device with a camera phone.

Topics

• surface
• polymer
• nickel
• simulation